如何从泛型类型参数中返回接口类型OperationContracts在我的 WCF REST 服务中？更具体地说，它适用于一个操作，但当我使用通用添加第二个操作时则不起作用T那是一个接口。
我使用 JSON 作为请求和响应格式，向非 WCF 客户端提供数据，该客户端解析 JSON 响应以获取所需的数据。我没有使用 SOAP 或服务生成的 WSDL。
我的服务接口：
[ServiceContract]
[ServiceKnownType("GetServiceKnownTypes", typeof(ServiceKnownTypesHelper))]
public interface IMyService
{
[WebGet(UriTemplate="count")]
[OperationContract]
IServiceResult<int> GetCount();
[WebGet(UriTemplate="desc")]
[OperationContract]
IServiceResult<string> GetDescription();
[WebGet(UriTemplate="foo")]
[OperationContract]
IServiceResult<IFooData> GetFooData();
// Fails when I invoke either method if I uncomment this operation.
//[WebGet(UriTemplate="bar")]
//[OperationContract]
//IServiceResult<IBarData> GetBarData();
}
I left GetCount() and GetDescription()在示例中指出这两个通用结果工作正常，但显然它们是具体类型。乃至GetFooData()工作正常，直到我添加第二种方法IServiceResult<T> where T是一个接口。
返回类型为GetFooData() and GetBarData()不一样，实现它们的具体类也不一样。
您可能会认为我已将实现简化为骨架，因为我不认为实现是问题的核心：
#region My service implementation
public class MyService : IMyService
{
public IServiceResult<int> GetCount()
{
return new ServiceResult<int>(42);
}
public IServiceResult<string> GetDescription()
{
return new ServiceResult<string>("Muffins");
}
public IServiceResult<IFooData> GetFooData()
{
return new ServiceResult<IFooData>(new FooData() { Foo = 99 });
}
public IServiceResult<IBarData> GetBarData()
{
return new ServiceResult<IBarData>(new BarData() { Bar = "Elvis was here" });
}
}
#endregion
#region ServiceKnownTypesHelper.GetServiceKnownTypes():
public static class ServiceKnownTypesHelper
{
private static IList<Type> serviceKnownTypes = new List<Type>()
{
typeof(FooData),
typeof(BarData),
typeof(ServiceResult<int>),
typeof(ServiceResult<string>),
typeof(ServiceResult<IFooData>),
typeof(ServiceResult<IBarData>),
};
public static IEnumerable<Type> GetServiceKnownTypes(ICustomAttributeProvider paramIgnored)
{
return serviceKnownTypes;
}
}
#endregion
#region IServiceResult<T> and its concrete implementation:
public interface IServiceResult<T>
{
IList<string> Errors { get; }
T Value { get; set; }
}
[DataContract]
public class ServiceResult<T> : IServiceResult<T>
{
public ServiceResult(T value)
{
this.Value = value;
}
private IList<string> errors = new List<string>();
[DataMember]
public IList<string> Errors
{
get
{
return this.errors;
}
}
[DataMember]
public T Value { get; set; }
}
#endregion
#region IFooData and its concrete implementation:
public interface IFooData
{
int Foo { get; set; }
}
[DataContract]
public class FooData: IFooData
{
[DataMember]
public int Foo { get; set; }
}
#endregion
#region IBarData and its concrete implementation:
public interface IBarData
{
string Bar { get; set; }
}
[DataContract]
public class BarData: IBarData
{
[DataMember]
public string Bar { get; set; }
}
#endregion
以及我调用时的错误消息GetBarData()从浏览器：
Type 'ServiceResult`1[IBarData]' cannot be added to list of known types since
another type 'ServiceResult`1[IFooData]' with the same data contract name
'http://schemas.datacontract.org/2004/07/ServiceResultOfanyType' is
already present.
错误消息的其余部分是关于冲突集合类型的红鲱鱼List<Test> and Test[]，这里的情况并非如此。
清楚地，IFooData and IBarData不一样，实现它们的类也不一样。
那么为什么要这样做ServiceResult<IFooData> and ServiceResult<IBarData>双方都决心ServiceResultOfanyType?
我是否遗漏了什么，或者没有办法解决这个问题？
